Q. No.Given below are two statements:
| Assertion (A): | Boron has a smaller first ionisation enthalpy than beryllium. |
| Reason (R): | The penetration of 2s electron to the nucleus is more than the 2p electron hence 2p electron is more shielded by the inner core of electrons than the 2s electrons. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
| Assertion (A): | Generally, ionisation enthalpy increases from left to right in a period. |
| Reason (R): | When successive electrons are added to the orbitals in the same principal quantum level, the shielding effect of inner core of electrons does not increase very much to compensate for the increased attraction of the electron to the nucleus. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
Correct statement(s) among the following are:
| (a) | Helium has the highest first ionisation enthalpy in the periodic table. |
| (b) | Chlorine has less negative electron gain enthalpy than fluorine. |
| (c) | Mercury and bromine are liquids at room temperature. |
| (d) | In any period, the atomic radius of alkali metal is the highest. |
Choose the correct option:
1. (a), (c), (d)
2. (a), (b), (c)
3. (a), (c)
4. (a), (d)
The correct order of ionization energy of W, X, Y and Z is-
| 1. | W > X > Y > Z | 2. | W < X < Y > Z |
| 3. | W < X > Y< Z | 4. | W > X > Y< Z |
In the following graph of variation of ionization energy with atomic number, X, Y, and Z represent elements.
The group number of X, Y, and Z elements is:
| 1. | 1st group | 2. | 15th group |
| 3. | 17th group | 4. | 18th group |
The graph between ionization energy and atomic number for the first group elements is shown below:
The element represented by Y in the graph above is:
1. Cs
2. Rb
3. Ca
4. K
Abnormally high ionization enthalpy of B as depicted in the graph below can be due to :
1. Completely filled 2p subshell.
2. Completely filled 2s subshell.
3. Completely filled 3d subshell.
4. Completely filled 4f subshell.
The correct graph depicting ionization energies for 2nd period elements is:
| 1. |  |
| 2. |  |
| 3. |  |
| 4. | None of the above |
| Assertion (A): | The first ionization energy of aluminum is lower than that of magnesium. |
| Reason (R): | The ionic radius of aluminium is smaller than that of magnesium. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | The ionization potential of Be (atomic no. 4) is less than that of B (atomic no. 5) |
| Reason (R): | The first electron released from Be is of p-orbital but that from B is of s-orbital. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True and (R) is False. |
| 4. | Both (A) and (R) are False. |
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